Advances in in the Design Synthesis of of Electromagnetic Bandgap Metamaterials

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1 Advances in in the Design Synthesis of of Electromagnetic Bandgap Metamaterials Douglas H. Werner, Douglas J. Kern, Pingjuan L. Werner, Michael J. Wilhelm, Agostino Monorchio, and Luigi Lanuzza

2 Overview EBG structures as as metamaterials Review of of standard EBG design approaches Multi-band EBG with fractal FSS elements EBGs with electrically small unit cells Genetic Algorithms for for AMC HIGP design Synthesis of of multi-band AMC HIGPs Synthesis of of multi-band AMC HIGPs with angular stability Synthesis of of meta-ferrites Design, fabrication, and testing of of low-profile SBWB antenna on on AMC HIGP

3 Electromagnetic Meta-materials Electromanetic Bandgap (EBG) (EBG) materials Multiband artificial dielectric meta-materials materials with with fractal fractal sphere sphere molecules Left-handed or or Double-Negative materials (including magneto-electric electric coupling) Meta-ferrite materials Bi-anisotropic meta-materials materials Human Human Lung Lung EBG EBG Materials Fractal Fractal Sphere Sphere Sponge Sponge

4 EBG High Impedance Surfaces Circuit Model: Simple parallel LC circuit can be used to represent the surface impedance C L D. Sievenpiper, L. Zhang, R. Jimenez Broas, N. Alexopolous, E. Yablonivitch, High-Impedance Electromagnetic Surfaces with a Forbidden Frequency Band, IEEE Trans. Antennas Propagat., vol. 47, n. 11, Nov

5 Original EBG or High-Z FSS Geometry Substrate Ground Plane h a w w l Metal Pattern w d Original Dimensions: e r = 1.2 h = 25 mil a = 12 mil w = 1 mil d = 27.5 mil l = 4 mil F. Yang, K. Ma, Y. Qian, T. Itoh, A uniplanar compact photonic-bandgap (UC-PBG) structure and its applications for microwave circuits, IEEE Trans. Microwave Theory Tech., vol. 47, Aug

6 Surface Impedance and Reflection Coefficient Impedance Sheet Zs Dielectric Slab d Ground Plane Z S jωl = 1 ( ω / ω) 2 ω = 1 LC Γ = Z Z S S + Z Z Z = 377 Ω = L =. 4nH C. 185 pf

7 EBG cells have multiple resonance modes originating from different portions of the cell Phase Angle (deg) Frequency (GHz) We can intentionally design an EBG for multimode behavior

8 Fractalized Multiband FSS Reflection Phase vs. Frequency Phase (deg) Frequency (GHz) FSS Cell Geometry: dx = dy =.5 cm ε = 1. 2 r h =.5 cm

9 Interdigitated Capacitance Higher capacitance lowers the resonant frequency for the same geometric footprint Phase Angle (deg) Frequency (GHz) Original Interdigitated

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11 Dual Band GPS and 4. GHz EBG FSS Cell Geometry: dx = dy = cm e r = 13 h = 5.8 mm (.2 in) Optimized for Zero Phase at and 4. GHz Result shows Zero Phase at and 4. GHz

12 Tri-band EBG FSS Cell Geometry: dx = dy = 3.4 mm e r = h = 4.97 mm Phase Angle (deg) Reflection Phase vs. Frequency Frequency (GHz) Optimized for Zero Phase at 3, 11 and 18 GHz Result shows Zero Phase at 3.7, 11 and 17.8 GHz

13 GA-HZ-FSS Dual-Band Design FSS Cell Geometry: dx = dy = 2.96 cm (l/6.4) er = 13 h =.293 cm Genetically-Optimized Dual Band EBG Phase (Degrees) Frequency(GHz) Measured Results Theoretical Simulation

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15 Comparison of Angular Stability Angular Stability of GHz Resonance 14 1 Phase (deg) Theta (deg) TE phase - original TE phase - optimized TM phase TM phase - optimized

16 Comparison of Angular Stability Angular Stability of 1.96 GHz Resonance Phase (deg) Theta (deg) TE phase - original TE phase - optimized TM phase - original TM phase - optimized

17 Artificial Ferrite Meta-materials (Meta-Ferrites) By By optimizing an an HZ-FSS design design for for the the appropriate values values of of Rs Rsand Xs, Xs, a high high frequency artificial ferrite ferrite meta-material material can can be be synthesized with with almost almost any any desired desired value value of of real real and and imaginary permeability. Improved microwave components and devices Substrate meta-materials materials for microstrip filters and antennas Electromagnetic absorbers Electronic packaging EMI / EMC HZ - FSS Structure h Ferrite Material with PEC Ground Plane d µ r = X s ω dµ R µ s r = ω dµ Surface Impedance: Z = R + jx s2 s s Surface Impedance: Z = Ztanh( g d) s1 Dielectric Permittivity: er = e r - je r Dielectric Permeability: m = m - jm r r r

18 Vias may be omitted from EBG designs Finite-sized EBG modeled with & without center-patch vias 1 Antenna Patterns 5 Gain [dbi] -5-1 No Via - Eplane (phi=) No Via - Hplane (phi=9) Via - Eplane (phi=) Via - Eplane (phi=9) Conclusion: Ground vias may be omitted from EBGs in antenna applications, even at steep grazing angles Theta [degrees] Huge improvement in manufacturability and manufacturing cost (25% - 4% savings).

19 Measurements of SBWB (Design 1) with Antenna E-Plane Cut Gain [dbi] GHz 1.8GHz Angle [degrees] E-Plane Cut Gain [dbi] GHz 2.GHz 2.1GHz Angle [degrees] E-Plane Cut Gain [dbi] GHz 2.3GHz 2.4GHz Angle [degrees]

20 Measurements of SBWB (Design 1) with Antenna H-Plane cut Gain [dbi] GHz 1.7 GHz 1.8 GHz Azimuth [degrees] H-Plane cut Gain [dbi] GHz 2 GHz 2.1 GHz Azimuth [degrees] H-Plane cut 1 Gain [dbi] GHz 2.3 GHz 2.4 GHz Azimuth [degrees]

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